Pork carcasses are typically cut into six initial portions, including the left and right front and hind quarters, and the left and right middles. The loin is part of the middle portion, adjacent the backbone in between the ribs and outer layer of back fat.
The conventional loin puller machine, which separates the loin from the carcass middle, has been substantially unchanged for approximately twenty years. One example of a prior art loin puller is from Acraloc, in Tennesee, as described in their U.S. Pat. No. 5,882,252.
The pork processing industry has had several long-standing problems with conventional loin pullers. In a conventional loin puller, a rotary scribe saw is provided to cut the meat. The scribe saw blade on a conventional loin puller is subject to wear and failure due to loads on the drive shaft. Since the blade operates at approximately 2,000 RPM, wear damage can occur quickly, leading to breakage of the blade. Such excessive wear can be the result of a side load on the drive gear shaft, which deflects the shaft and thereby deflects the blade, which then rubs on the standard. Breakage of the blade is a significant safety hazard.
A typical loin puller can process 1,300 pork middles per hour. Cutting accuracy is critical. For example, if the scribe saw cuts into the rib bone then the primary meat cutting blade cuts through the bone more than one-quarter inch into the belly underneath. That part or the belly, which later becomes bacon, then falls off causing yield loss. If the scribe saw cut is too shallow, when the meat cutting blade tries to pass through the scribe saw blade path, without the bone being cut all the way through. This partial bone cut results in major bone damage, with chips of broken bone distributed throughout the meat.
Another problem with the conventional loin puller is wear and damage to the various shafts. The pinion, which is mounted on the drive motor shaft, has a tendency to float along the shaft, thereby promoting uneven wear on the motor shaft and associated gears. Furthermore, the pinion shaft is typically connected to a motor drive shaft via a single keyway, which generates pressure on only one side of the motor shaft, which can lead to complete failure of the motor shaft. Also, because the ball bearing between the pinion shaft and motor shaft has very limited contact only at the point where the ball is touching the shafts, the longevity of the bearing, motor shaft, and pinion shaft is compromised. The single bearing use in a conventional loin puller also causes the ring or bevel gear and pinion gear to misalign due to flexing, thereby leading to excessive wear and breakage of the shafts and/or the scribe saw blade.
Therefore, a primary objective of the present invention is the provision of an improved scribe saw head assembly which overcomes the problems of the prior art.
A further objective of the present invention is the provision of a scribe saw head assembly for a loin puller having an improved pinion to minimize wear and damage.
Yet another objective of the present invention is the provision of a loin puller scribe saw assembly having a pinion with a radial flange to support a bearing.
A further objective of the present invention is the provision of a scribe saw head assembly for a loin puller which minimizes risk of shaft or blade damage.
Another objective of the present invention is the provision of a scribe saw head assembly for a loin puller which increases the life expectancy of the scribe saw blade and other components.
Another objective of the present invention is the provision of a scribe saw head assembly for a loin puller which is economical to manufacture, and simple, safe and durable in use.
These and other objectives become apparent from the following description of the invention.